Such operating mechanisms are known in numerous designs. Illustratively they are used to open and close a window, a door or the like, a handle being designed to rotate—most often using an actuating element such as a spindle, hereafter “square bar”—a drive system, for instance a window drive or a door lock socket, the latter hereafter being called “lock ‘hub’”.
In general the actuating element must transmit in addition to torques also axial tractions for instance to door fittings. The linkage between the handle and the actuating element therefore must be designed that they shall be firmly anchored to each other both axially and irrotationally after installation, and, depending on the window or door design, the square bar connection must be matchable to the particular thickness of the window frame or door wing.
For that purpose the German patent documents 1,927,916 U1 or 1,937,220 U1 employ square bars divided each in two, where substantially wide slots fitted with wedging surfaces are fitted to the ends of the two bar halves, said wedging surfaces tapering in two directions and an expansion screw engaging in-between said surfaces. The elongated geometry of said slots allows affixing the square bar in axially variable manner and thereby to adapt to the particular door thickness. The expansion screw turned into the handle neck however may project from the handle, being unesthetic and also a potential for injury. Moreover manufacture is fairly costly because each square bar requires both a right-hand and a left-hand half a bar; production and storage therefore are doubly onerous. Installation is cumbersome and requires tools.
The German document 86 05 427 U1 uses a specially designed threaded rod to implement door handle connection, said rod acting on external edges above longitudinal grooves of two similar/identical square bar halves between which it shall be compressed when being screwed into them. The onion-like tip of the threaded rod rests in a V-shaped cavity against the displaced material of the halves of the square bar. This design also requires separate fitting and installation to affix the actuating element in the handle, the strength of the mechanical connection depending on the appropriate affixation of the threaded rod. This rod impairs the surfaces and edges of the square bar halves in lasting manner, and as a result repeated installation is possible only conditionally. Furthermore when being sufficiently stressed, the square bar halves may shift relative to each other, in which event durable axial affixation may become problematical.
Other improvements in axial dimensional stability and in meeting manufacturing tolerances make use of solid square bars in conjunction with slotted leaf spring elements or corrugated springs (see for instance the German patent document DE 2,024,652 A). In the European patent document EP 0,436,795 B1, the connecting bar is fitted with a continuous longitudinal groove at one side and with a terminal blind hole comprising shoulders to support the angled ends of an elongated leaf spring. The longitudinal groove in the square bar helps inserting the mounting screw into a terminal leaf spring longitudinal slot which is narrower than the terminal widening of the mounting screw. In this manner it includes a special stress because the leaf spring's corrugated zone axially locks the connecting bar in the lock hub. Both manufacture and storage of such a connection system are also onerous. Installation requires several elements and the particular applicable tool always must be at hand.